直流系统保护对交流故障的响应机理与交流故障引发的直流系统保护误动分析  

Response Mechanism of UHVDC System Protection to Faults in UHVAC System and Analysis on Malfunction of UHVDC Protection Caused by Faults in UHVAC System

作　　者：李佳曼[1] 蔡泽祥[1] 李晓华[1] 赵建宁[2] 周全[2] 王海军[2] 张胜慧[2] 吕金壮[2] 

机构地区：[1]华南理工大学电力学院,广东省广州市510640 [2]中国南方电网超高压输电公司,广东省广州市510620

出　　处：《电网技术》2015年第4期953-960,共8页Power System Technology

基　　金：国家高技术研究发展计划(863计划)(2012AA050209);国家自然科学基金项目(51377059)~~

摘　　要：针对交直流混联系统中直流保护在交流系统故障时误动的问题,基于某特高压直流系统的数字实时仿真系统(RTDS),研究交流故障下直流系统的暂态响应特征。从交流故障与直流故障的相似性、直流保护原理和整定方法的不完善性两方面揭示了直流保护对交流故障的响应机理。基于直流保护对交流故障的响应机理,全面梳理出在原理上能反映交流故障的直流保护类型。结合某特高压直流系统的RTDS实验数据,详细分析了两侧交流系统故障时的低电压特征以及电流失衡特征所引发的直流保护误动情况。深入分析了交流故障下直流低电压保护、阀组差动保护以及桥差保护的误动机理,并提出相应的改进建议,为直流工程的更合理运行提供指导。To solve the malfimction of protection of UHVDC transmission system in a UHV AC/DC hybrid system caused by the faults occulted in UHVAC system, the RTDS closed-loop test system of a certain UHVDC transmission project is utilized to research the transient response characteristic of DC protection under AC faults and the malfunction of DC protection caused by AC faults. The response mechanism of DC protection to AC faults is revealed by two aspects, namely the similarity between AC faults and DC faults as well as the imperfection of both protection principle and setting method of DC protection. Based on this response mechanism, the types of DC protections, which can reflect AC faults in principle, are summarized. Combining with RTDS experimental data of a cei＇tain UHVDC transmission system, the low-voltage characteristics of AC and DC system under faults occurred in AC systems at both sides of DC system and the malfunction of DC protection due to current unbalance characteristics are analyzed in detail. The malfunction mechanism of DC low-voltage protection, valve group differential protection and bridge differential protection under AC faults is analyzed in depth, and corresponding improvement suggestions are put forward.

关 键 词：特高压直流系统 交流故障 响应特征 直流保护 

分 类 号：TM721[电气工程—电力系统及自动化]